One fundamental difference between a particle and its antiparticle is the?

Question

One fundamental difference between a particle and its antiparticle is the...

charge, if the particle has a charge.

number of quarks contained in each particle.

mass.

spin.

Answer 1

Its charge.

Answer 2

charge. Number of quarks is the same (although not necessarily the same types of quarks) and mass and spin are the same.

Answer 3

Antiparticles are the same as particles except they hold an opposite charge (electron/positron, etc.)

I assume this is a multiple guess type question, and finding one right answer means I don't have to dispute the distractors (wrong answers).